Air dropped antenna with deployment apparatus

ABSTRACT

Antenna deployment apparatus for an air-launched electronic buoy having a self-erecting main antenna element and a plurality of self-erecting, radiating ground plane antenna elements which are retained during descent in undeployed, spirally wound conditions by a spring loaded housing assembly in turn maintained in deployment preventing position by a pivotally mounted latch which is pinned in interlocking engagement with a pair of locking posts. At some time after landing, a timer activates an explosive squib to force the latch to shear a pin and move to a releasing position causing assembly ejection which facilitates antenna deployment and parachute separation.

United States Patent Inventors Appl. No.

Filed Patented Assignee David W. Spoonamore Monroeville;

Kenneth A. Renno, Fort Wayne; Paul E. Kite, South Whitley, Ind.

Aug. 12, 1969 Mar. 2, 1971 the United States of America as represented by the Secretary of the Navy.

AIR DROPPED ANTENNA WITH DEPLOYMENT APPARATUS 10 Claims, 3 Drawing Figs.

Int. Cl IIOlg 1/28 Field of Search 343/705 {56] References Cited UNITED STATES PATENTS 2,979,608 4/1961 Sirons 343/720 Primary Examiner-- Eli Lieberman Attorneys-Edgar J. Brower, Henry Hansen and B. Frederick Buchan, Jr.

ABSTRACT: Antenna deployment apparatus for an airlaunched electronic buoy having a self-erecting main antenna element and a plurality of self-erecting, radiating ground plane antenna elements which are retained during descent in undeployed, spirally wound conditions by a spring loaded housing assembly in turn maintained in deployment preventing position by a pivotally mounted latch which is pinned in interlocking engagement with a pair of locking posts. At some time after landing, a timer activates an explosive squib to force the latch to shear a pin and move to a releasing position causing assembly ejection which facilitates antenna deployment and parachute separation.

PATENTEU m 2m: 3568.201

sum 1 [1F 2 INVENTORS DAVID W. SPOONAMORE KENNETH A. NNO PAUL E. Kl

AIR DROPPED ANTENNA WITH DEPLOYMENT APPARATUS STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION The invention generally relates to self-erecting antenna systems and, more particularly, to means for deploying the antenna systems of air-launched electronic gear after implantation of the gear.

Previously known air-launched electronic gear has included antenna deployment systems which were operated during parachute descent. Such systems were subject to failure because of antenna element damage caused by shock forces attributable to landing impact or by entanglement in foliage through which the gear may fall. It is desirable that antenna deployment apparatus not only bevof a size and weight permitting incorporation in existing sonobuoy configurations to enable use of conventional sonobuoy launching apparatus but also have a design assuring positive disengagement of the gear from the parachute to prevent entanglement of the elements in the parachute suspension lines. Further, the apparatus must be capable of being safely handled, subjected to flight incident vibration and accelerations and stored without risk of inadvertent antenna deployment.

SUMMARY OF THE INVENTION A general purpose of this invention is to provide reliable, impact resistant, deployment apparatus which overcomes the deficiencies of previously known apparatus and assures antenna deployment after impact.

Briefly, the general purpose and'other objects of the invention are accomplished by providing self-erecting antenna elements which may be spirally wound and captured within element receiving cavities by a spring loaded, releasably latched, housing assembly. Further, the invention comprehends entrapping ground plane antenna elements in cavities formed in an antenna mounting block with a sleeve forming part of the housing assembly. The invention comprehends a pair of locking posts formed for interlocking engagement by a shear pin-retained latch mounted for pivotal movement to a releasing position in a plane normal to the anticipated impact force loading direction in response to a timer activated squib. A feature of the invention includes attaching the parachute to the housing assembly to insure against antenna element entanglement with the parachute upon antenna deployment. It is also contemplated that the housing assembly carry a coil spring of 55 sufficient size to eject the housing assembly upon latch releasement and enable unimpeded antenna element deployment.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 represents an isometric view of the antenna carrying end of an air-launched electronic buoy with an ejected housing assembly and deployed antenna elements;

FIG. 2 represents an end view of the buoy of FIG. 1 with the housing assembly arranged to prevent antenna deployment;

FIG. 3 represents a longitudinal view in cross section of the buoy antenna end and the housing assembly of FIG. 2 taken generally along line 3-3 of FIG. 2; and

FIG. 4 represents a block diagram of the electrical system for actuating antenna deployment.

DESCRIPTION OF THE PREFERRED EMBODIMENT Generally, as shown in FIG. I, the electronic gear to be implanted after air-launching is housed in a buoy 10 of generally elongated cylindrical configuration one end of which (not shown) .is formed to pierce the ground upon impact and implant the buoy 10 in a generally upright orientation supporting the antenna carrying end, shown in FIG. ll, above ground level. A generally cylindrical antenna mounting block 11 having four peripherally spaced cavities 11a symmetrically aranged about its lateral periphery is coaxially mounted on the upper end of the buoy 10. Each cavity Illa is sized to envelop a respective ground plane antenna element 12 in a spirally wound condition, each element 12 having one end attached by a bolt 13 to the mounting block 11. Asshown in FIGS. 1 and 3, the antenna mounting block 11 is capped by an end plate 15 made of insulating material and having a pair of semicylindrical bosses 15a arranged on opposite sides of a slot 15b communicating with an axially extending duct 11b formed in the mounting block 11 and through which extends the main antenna element 17. The elements 12 and 17 are made of a material such as spring steel so that they generally tend to erect themselves to their operating orientations from spirally wound positions. A pair of cylindrical locking posts 18 having annular locking grooves 18a formed about their protruding ends are threaded into the mounting block 11 through the end plate 15. As shown in deployed condition in FIG. 1, the antenna system thereby includes the main element 17 generally extending longitudinally of the buoy 10 and four radiating ground plane elements 12 extending generally radially of and perpendicular to the buoy axis.

The antenna elements 12 and 17 are maintained in undeployed condition by a housing assembly 19 shown in cross section in FIG. 3. A generally cylindrical latch mounting member 20 of smaller diameter than the block 11 has a pair of longitudinally extending bores 200 which slidably receive the locking posts 18 and has a cavity 20b extending thereinto from the antenna adjacent side which is sized to receive the main antenna element 17 in a spirally wound condition. The cavity 20b is sufficiently large not only to receive the element 17 and permit an abutting relation of the mounting member 20 with the end plate 15 but also is sufficiently large to prevent permanent deformation of the furled element 17. A latch 23 more particularly shown in FIG. 2 is pivotally mounted intermediate its ends in a transversely extending groove 200 formed in the obverse end of the member 20 by a bolt 24 and has semicircular notches 23a extending into opposite sides of respective ends which are formed for interlocking engagement with the grooves 18a of the locking posts 18. During assembly, a shear pin 25 is threaded through the latch 23 in locking position into the member 20 to restrain the latch 23 from moving from locking position to a releasing position shown in dashed lines in FIG. 2.

In order to entrap the ground plane elements 12 in their spirally wound conditions in the cavities 11a, the housing assembly 19 includes a tubular sleeve 30 which is slidably received over the protruding end of the antenna mounting block 11 and closes the cavities Ila. The sleeve 30 includes fixed therewithin an internal transverse bulkhead 31 which divides the sleeve into a pair of chambers one of which contains the latch 23 and mounting member 20 and the other of which is sized to receive a folded parachute 32. The bulkhead 31 normally abuts the mounting member 20 and is fixed thereto by bolts such as 33 also used to install a pair of bridle riser lugs 34 to which ends of the risers 35 of a parachute bridle are attached. The other ends of the risers 35 are connected to a swivel 36, in turn connected to the suspension lines 37 of the parachute 32 which may be of the ring vortex or other drogue types.

A coil spring 39 is interposed in compression between the end plate 15 and the bulkhead 31 in the annular space between the sleeve 30 and the mounting member 20 and is attached at one end of the bulkhead 31. Movement of the latch 23 to releasing position permits the spring 39 to eject the member 20 and the sleeve 30 thereby permitting the selferecting antenna elements 12 and I7 to deploy.

As shown in FIG. 2, an electrically fireable pyrotechnic squib 41 is fixed to the member 20 adjacent the groove 20c and has a plunger 42 which bears against the latch 23 in locking position. The squib 41 is of a conventional type which responds to the application of a voltage of a predetermined size to force the plunger 42 in a direction to cause the shear pin 25 to be sheared and force rotation of the latch 23 to releasing position. As shown in FIG. 4, a convenient firing circuit 40 for enabling activation of the squib 41 at the appropriate time after impact comprises a power supply 45 such as the buoy battery which applies a voltage through a switch 46 to activate a timer 47 connected to apply a firing signal to the squib 41 after a predetermined delay. The switch 46 may be any of the well-known types which are actuated as by a static line upon launching of the buoy from an aircraft or upon deployment of the parachute 32. The timer 47 may conveniently be of a charging capacitor type which takes a predetermined time to build up its output voltage to the necessary level to activate the squib 41. The delay in time imposed by the timer 47 between the operation of the switch 46 and the activation of the squib 41, of course, depends on the anticipated descent time of the buoy 10 to its implanted position.

When the squib 14 is activated, the plunger 42 forces the pin 25 to be sheared and the latch 23 to be moved from locking position to the releasing position. The rotational excursion of the latch 23 is, of course, limited by the boundaries of the groove 200. The spring 39 urges the housing assembly 19 to be ejected as is generally indicated in P10. 1. The ground plane elements 12 and the main antenna element 17 are thereupon freed to uncoil or unfurl to their operating orientations. The force of the spring 39 is strong enough to eject sleeve 30, the released latch 23 and the mounting member 20, and also the bridle risers 35 and the parachute 32 to noninterfering positions relative to the implanted buoy 10.

in assembling the buoy 10, the ground plane elements 12 are rolled up and positioned within the cavities 11a and temporarily held in place by spatulalike retaining members (not shown) which may be bolted to the lateral periphery of the buoy 10 in spaced relation to the recessed boss portion of the antenna mounting block 11. Thereafter, the antenna element 17 is rolled up and the mounting member 20 having the latch 23 in releasing position is slipped down over the mounting posts 18 into abutment with the end plate 15, the rolled up antenna element 17 being positioned within the cavity 20b. Thereafter, the latch 23 is rotated to interlockingly engage the posts 18 and the shear pin 25 is threaded into the member 20 to retain the latch 23 in locking position. The sleeve 30 is then slid down into element entrapping position within the encirclement of the temporary retaining members (not shown) to force the spirally wound ground plane elements 12 completely within the cavities 11a of the antenna mounting block 11. Since the elements 12 are spirally wound about axes extending perpendicularly of the sleeve axis, the lower edge of the sleeve functions as a frictional restrainer during the process of gradually forcing all of the wound elements 12 to rotate from abutment with the temporary retaining elements into the cavities 110 with a minimal risk of undesirable permanent deformation of the elements 12. If the spring 39 has not been precompressed, it is fully compressed against the plate by forcing the bulkhead 31 to seat against the latch mounting member 20. The bulkhead 31 is then attached to the member by other bolts (not shown) and by the bolts 33 when the bridle lugs 34 are installed. Thereafter, the parachute 32 is packed in the space provided.

The invention therefore provides antenna deployment apparatus which assures deployment of the antenna array at a time after impact in spite of the severe shock forces experienced at impact. The latching system remains operable to eject the spring loaded housing assembly 19. Deployment of the antenna system is simultaneously accompanied by separation of the parachute 32 which is removed to a noninterfering position. After the buoy 10 is assembled, the latch 23 cannot be inadvertently moved to release the assembly 19 for ejection by shock, vibration or other forces not imparted by the squib plunger 42. Therefore, the buoy 10 may be handled and stored in safety and subjected to incident vibration and accelerations during flight.

Obviously many modifications and variations of the present invention are possible in view of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. Antenna deployment apparatus for an air-launched electronic gear comprising:

an antenna mounting block;

a first antenna element connected to said mounting block and being self-erecting from an undeployed condition to a deployed condition;

a housing assembly for entrapping said antenna element in said undeployed condition when said assembly in interconnected with said mounting member;

latching means for releasably interconnecting said housing assembly to said mounting block, said latching means including a latch mounted for pivotal movement between locking and releasing positions in a plane normal to the direction of landing impact force loading and including actuating means having a plunger arranged for movement in said plane to force said latch from locking position to releasing position; and

spring means for ejecting said housing assembly from said mounting block upon movement of said latch from said locking position to permit said antenna element to erect itself in said deployed condition.

2. Apparatus according to claim 1 further comprising:

said first antenna element being made of a flexible, spring material and being wound upon itself in said undeployed condition; and

said housing assembly includes formed in a side adjacent said antenna mounting block a cavity sized to receive said first antenna element in said undeployed condition.

3. Apparatus according to claim 1 further comprising:

a second antenna element connected to said mounting block and being self-erecting from an undeployed condition would upon itself to a deployed condition extending in a direction transversely of the direction of said deployed condition of said first element;

said antenna mounting block includes a cavity found in its lateral periphery for receiving said second element in said deployed condition; and

said housing assembly includes a projection for entrapping said second element in said cavity formed in said mounting block.

4. Apparatus according to claim 3 further comprising:

said first antenna element being made of a flexible, spring material and being wound upon itself in said undeployed condition; and

said housing assembly includes formed in a side adjacent said antenna mounting block a cavity sized to receive said first antenna element in said undeployed condition.

5. Apparatus according to claim 1 further comprising:

a plurality of second antenna elements made of flexible, spring material, connected to said mounting block in spaced relation and being self-erecting from undeployed conditions wound upon themselves to deployed conditions extending transversely of the deployed condition of said first antenna element;

- said mounting block has a cylindrical configuration and has a plurality of cavities formed in its lateral periphery in spaced relation and sized for receiving respective ones of said second antenna elements in said undeployed conditions; and

said housing assembly includes a tubular sleeve sized to receive said cavitied portion of said mounting block and entrap said plurality of said second elements in said cavities.

6. Apparatus according to claim 5 further comprising:

said first elementbeing made of aflexible, spring material and being wound upon itself in said undeployed condition;

said housing assembly including a latch mounting member connected within said sleeve, said member having formed in one end adjacent said antenna mounting member a cavity sized to receive said first antenna element and having a pair of spaced apart, parallel bores formed to extend therethrough from said one end;

a pair of locking posts connected to said antenna mounting block and being slidably received through said bores and protruding from the other end of said latch mounting member; and I said latch being pivotally mounted intermediate its ends on said other end of said latch mounting member and being formed for interlocking engagement with said locking posts.

7. Apparatus according to claim 6 further comprising:

said latch member has a lateral periphery apaced inwardly of the inner periphery of said sleeve; and

said spring means includes a coil spring connected at one end to said housing assembly, positioned in the annular space between said sleeve and said latch mounting member and compressed between said housing assembly and said antenna mounting block.

8. Apparatus according to claim 7 further comprising; a

shear pin extending through said latch and connected to said latch mounting member for retaining said latch in said locking position, said shear pin being shearable by said plunger forcing said latch from saidlockingposition'.

9. Apparatus according to claim 8 wherein said latch activating means comprises:

power supply means for supplying electrical power;

switch means connected to said power supply means and being actuatable prior to landing for providing power;

timer means electrically connected to receive power from said switch means and being responsive to the application of electrical power for providing a firing signal after a predetermined time longer than a predetermined descent time; and v explosive squib means including said plunger and being responsive to said firing signal for causing said plunger to force said latch from said locking position.

10. Apparatus according to claim 9 further comprising:

a transverse bulkhead connected within and dividing said sleeve into a parachute receiving compartment and a latch mounting member receiving compartment;

said other end of said latch mounting member abutting and being connected to said bulkhead and having a groove formed therein within which is mounted said latch in recessed relation;

a parachute having a bridle connected thereto; and

lug means connected to said latch mounting member for interconnecting said bridle to said bulkhead. 

1. Antenna deployment apparatus for an air-launched electronic gear comprising: an antenna mounting block; a first antenna element connected to said mounting block and being self-erecting from an undeployed condition to a deployed condition; a housing assembly for entrapping said antenna element in said undeployed condition when said assembly in interconnected with said mounting member; latching means for releasably interconnecting said housing assembly to said mounting block, said latching means including a latch mounted for pivotal movement between locking and releasing positions in a plane normal to the direction of landing impact force loading and including actuating means having a plunger arranged for movement in said plane to force said latch from locking position to releasing position; and spring means for ejecting said housing assembly from said mounting block upon movement of said latch from said locking position to permit said antenna element to erect itself in said deployed condition.
 2. Apparatus according to claim 1 further comprising: said first antenna element being made of a flexible, spring material and being wound upon itself in said undeployed condition; and said housing assembly includes formed in a side adjacent said antenna mounting block a cavity sized to receive said first antenna element in said undeployed condition.
 3. Apparatus according to claim 1 further comprising: a second antenna element connected to said mounting block and being self-erecting from an undeployed condition would upon itself to a deployed condition extending in a direction transversely of the direction of said deployed condition of said first element; said antenna mounting block includes a cavity found in its lateral periphery for receiving said second element in said deployed condition; and said housing assembly includes a projection for entrapping said second element in said cavity formed in said mounting block.
 4. Apparatus according to claim 3 further comprising: said first antenna element being made of a flexible, spring material and being wound upon itself in said undeployed conditioN; and said housing assembly includes formed in a side adjacent said antenna mounting block a cavity sized to receive said first antenna element in said undeployed condition.
 5. Apparatus according to claim 1 further comprising: a plurality of second antenna elements made of flexible, spring material, connected to said mounting block in spaced relation and being self-erecting from undeployed conditions wound upon themselves to deployed conditions extending transversely of the deployed condition of said first antenna element; said mounting block has a cylindrical configuration and has a plurality of cavities formed in its lateral periphery in spaced relation and sized for receiving respective ones of said second antenna elements in said undeployed conditions; and said housing assembly includes a tubular sleeve sized to receive said cavitied portion of said mounting block and entrap said plurality of said second elements in said cavities.
 6. Apparatus according to claim 5 further comprising: said first element being made of a flexible, spring material and being wound upon itself in said undeployed condition; said housing assembly including a latch mounting member connected within said sleeve, said member having formed in one end adjacent said antenna mounting member a cavity sized to receive said first antenna element and having a pair of spaced apart, parallel bores formed to extend therethrough from said one end; a pair of locking posts connected to said antenna mounting block and being slidably received through said bores and protruding from the other end of said latch mounting member; and said latch being pivotally mounted intermediate its ends on said other end of said latch mounting member and being formed for interlocking engagement with said locking posts.
 7. Apparatus according to claim 6 further comprising: said latch member has a lateral periphery apaced inwardly of the inner periphery of said sleeve; and said spring means includes a coil spring connected at one end to said housing assembly, positioned in the annular space between said sleeve and said latch mounting member and compressed between said housing assembly and said antenna mounting block.
 8. Apparatus according to claim 7 further comprising; a shear pin extending through said latch and connected to said latch mounting member for retaining said latch in said locking position, said shear pin being shearable by said plunger forcing said latch from said locking position.
 9. Apparatus according to claim 8 wherein said latch activating means comprises: power supply means for supplying electrical power; switch means connected to said power supply means and being actuatable prior to landing for providing power; timer means electrically connected to receive power from said switch means and being responsive to the application of electrical power for providing a firing signal after a predetermined time longer than a predetermined descent time; and explosive squib means including said plunger and being responsive to said firing signal for causing said plunger to force said latch from said locking position.
 10. Apparatus according to claim 9 further comprising: a transverse bulkhead connected within and dividing said sleeve into a parachute receiving compartment and a latch mounting member receiving compartment; said other end of said latch mounting member abutting and being connected to said bulkhead and having a groove formed therein within which is mounted said latch in recessed relation; a parachute having a bridle connected thereto; and lug means connected to said latch mounting member for interconnecting said bridle to said bulkhead. 